Heat-resisting surface



F. A. FAHRENWALD HEAT RESISTING SURFACE March 31,'1931.

Filed Sept. 27, 1928 2 Sheets-Sheet l F. A. FAHRENWALD HEAT 11115151111@SURFACE Filed sep-11 27, 192s March 31, 1931.

2 Sheets-Sheet 2 latented Mar. 3l, 193i UNl'lED PATENT OFFEEHEAT-RESIST'ING SURFACE .apnic-anon sie@ september 2r, was. serial No.308,627.

This invention relates to heat resisting me-V tallic surfaces, such, forexample, as furnace hcarths, dampers, and the like, and 1s illus-vtrated. herein as embodied in a heat resisting 5 surface of the samegeneral construction as those disclosed in United States Letters PatentNos. 1,629,689 and 1,643,766, granted May 24C, 1927 and Sept. 27, 1927,respectively, upon applications filed in my nameu l@ Prior to theprovision of the inventions' disclosed in the said Letters Fatents,furnace hearths and the like comprised generally, a single large pieceof alloy having a dat upper surface, or a relatively small number oflarge l5 pieces of alloy that combined to present aV surface of thedesired area. ln charging such furnaces as those of the open hearthtype, it is customary simply to throw in or otherwise deliver, coldcastings, forgings, 2U etc., to the large metallic hearth surface whilemaintaining the latter at a high temperature, and, owing to the factthat metals and alloys ofthe class generally known as heat resisting,possess a. rate of expansion w considerably higher than is possessed bymost refractory materials, it will be appreciated that in the use ofhearths of the old, single piece type, the introduction of the coldmetallic castings or forgings onto isolated Ml areas of the large hearthcaused those areas to chill andI to contract. As a result of thisaction, heart-hs composed of fairly thick metal would flow under tensionor compression and eventually crack.L @n the other hand, if the metal ofthe hearth was relatively thin and flexible, it would 'warp completelyout of shape in accommodating; its surface .contour to internaldimensional changes brought about by the fluctuations in 40 temperatureof its different portions.` Thus,

one of the heavier and thiclrer hearths would' not tend to warp as muchas one of the relatively thin types, but it would tend to flow andbecome of uneven thickness which, of

'i5 course, was about equally undesirable.

lin view of this tendency onthe part of liearths generally in use priorto the inven tions disclosed in my above mentioned lietters Patents, andstill being used in some 5U quarters, it was proposed by me inthe saidpatents to reduce warping and cracking by forming the hearth of a largenumber of small castings laid edge to edgey and connected together bymeans of interengaging portions. lrlhus, inthe practice of my formerinventions, the plates areismall and of a suilicient thickness that if achange in temperature is imparted to one portion of a plate, conductioncurrents will be set up and before being warped or otherwise damaged, 6othe .small plate will assume a uniform teun perature throughout, whichwill result in a uniform expansion or contraction being imparted to theplates.

1While the inventions set forth in the Let 65 ters Patents mentioned arevery dsatisfactory in operation and constitute marked advances over theprior art, it has been found desirable, and is accordingly an importantobject of the present invention, to provide a hea-t resisting surfacewhich permits unlimited expansion of the plates without tending to bendor buckle them. lt will be appreciated that a surface composed of aplurality of small heat resisting plates closely laid in edge to edgerelation with one another cannot expand unlimitedly in the direction ofthe plane of the plates, and if a high degree of expansion is imparted,the plates may en'- gage one another in some fashion and buckle, au orthe plates may become unduly separated whereby the spaces between theedges of adjacent plates will become widened; a result which may not bedesired.

lt is accordingly an important feature of the invention, which isconduciveto the ac complishment of the recited object, to provide a heatresistingr surface composed of a number of heat resisting platesarranged to present an unbroken work engaging surface irrespective ofexpansion or contraction imparted to the plates. As illustrated, theplates are disposed with their adjacent edges loosely overlapping oneanother, whereby the plates may undergo dimensional changes withoutopposition and without destroying the unbroken continuity of the heatresisting, work engaging surface.

Another feature of the invention which aims towards the accomplishmentof the re- 10 lll) cited object consists in the elimination of fastenersor fastening elements extending between the small heat resisting plates,whereby each plate is free to change dimensionally without exerting anytendency to change dimensionally the remaining plates. The plates are,as hereinbefore pointed out, arranged to overlap, and they are held inassembled relation with one another by reason4 of being attached tosupporting members, and not through joining adjacent plates by means ofinterengaging parts. Thus each plate member may expand or cont-act, or,in the event that such should occur, warp or bend,

freely independently of the remaining plates.

Still another feature of the invention consists in the provisionof anovel connection between the member or members comprising the heatresisting surface, and the member, or members, which support the heatresisting surface. ils illustrated, the connection disclosed hereinpermits ready removal of the heat resisting plates when the latter aremanually moved into a particular position, and prevents removal of theplates in all other positions. Furthermore, the connectiontl arearranged to permit unrestricted expansion of therplates in alldirections and, as shown, they comprise broadly a plurality of partscarried by the supporting members and a plurality of interfitting partscarried by the heat'resisting plates, in such a manner that theconnection may be rendered effective or ineffective merely byint'erli-tting the parts without the use of any separate securing orfastening means whatsoever. Such a provision simplifies and improves notonly the construction of the heat resisting surface but likewise itsassemblage and disassemblage.

@ther objects and features of the invention will become apparent from areading of the following specification in the light of the accompanyingdrawings, in which- Figure is a view in elevation in section of furnacehaving a hearth' of the improved type mounted therein;

Figure is a plan view of the furnace and hearth that are shown in Figure1;

Figure 53 is a View in side elevation in section of the furnace andhearth that are shown in Figures and 2;

Figure llis a lower plan view of one of a series of heat resistingplates which comprise 'theI hearth shown in the preceding figures;

igure li is a perspective view showing a supporting :member or elementwhich is adapted to rest upon the floor of the furnace and to supportthe hearth.

Turning now to the drawings, the reference numeral v.l0 indicates thebottom of a furnace that is provided with side walls 12, 12 and an endwall 11i. rlhe furnace, of course, may be of any desired type for it isto be appreciated that the invention is capable of apincenso plicationto furnaces of practically every type, and may be employed in a numberof other usages in which it is desired to provide a metallic heatresisting surface. Usages comprise linings for furnaces, dampers,grates, baliles, flues, etc. lt is for the purpose of illustration only,that the invention is shown hercin as embodied in a furnace hearth.

A. plurality of supporting elements, or members, 16 and 18 are disposedlongitudinally of the furnace, and comprise metallic rails, or bars,spaced apart and disposed par allel to one another.v As shown moreclearly in Figures 1 and 5, each of the supporting members 16 and 18comprises a base 20 having a plurality of upwardly extendingianges orribs 22 formed integrally with the central, longitudinal portion of thebase, and with outwardly flared lug engaging portions 24. As shown inFigure 2, the lug engaging portions are narrower than the base portion20 of the supporting members, and as shown in Figure 1, the lug engagingportions are flared out to provide a series of equally spaced recessesor pockets having restricted openings. The supporting members are soformed and placed within the furnace that each opening in one of themembers has a corresponding opening in the other member located directlyopposite the first opening.

The hearth itself is composed of a plurality of heat resisting plates26, 26 which, as shown in Figures 1, 3 and Ll, are provided with aplurality of connecting portions, each of which comprises a downwardlyextending forward wall or projection 28, a lug portion 30 extendingforwardly from the lower extremity of the wall 28 and having an upperface substantially parallel to the upper face of plate 26 and aplurality of side walls 32, 82 extend ing rearwardly and upwardly fromthe op posite sides of the forward wall 30. The arrangement justdescribed is in the form of a pocket with a lug projecting from theforward side thereof, and as illustrated each of the heat resistingplates 26 is provided, as shown in Figure ll, with a plurality of thesepockets, it being understood that the number of pockets provided willcorrespond to the number of supporting members 16 and 18. The lugs 30 ofthe plates are arranged to lit within the recesses formed between thelug engaging portions of the supporting elew ments, as shown in thedotted lines at the right of Figure l. ln this view, a heat resistingplate disposed vertically, with the lug pointing downwardly, has beenmoved into such a position that the lug projects through. the openingformed between adjacent lug engaging portions, and is now free to beswunf downwardly to the left as viewed in the saidflgure to assume theposition shown in solid lines, When so positioned the side walls 32 and32 of a pocket engage the sides of the flared-out portions 2li and 24 ofthe supporting members thereby preventing lat- I eral displacement of aplate relatively to the members; the rear face of the forward wall 28 ofthe plate engages an edge ofan adjacent flared-out portion and the frontface of the forward wall engages an edge of another adjacent flared-outportion 'whereby horizontal .displacement of the 'plate longitudinallyof the hearth is prevented; and the upper face of the lug 30 engages theunderside of an adjacent flared-out portion of the supporting railthereby preventing vertical bodily displacement of th-e plate 26. Thus,it will be seen that by the provision of this hinge-like connection, theplates are prevented' from becoming accidentally displaced, but, if itis desired to replace a warped, brok-en, or bent plate, this may be donemerely by swinging it to a vertical position liftingy it out andinserting in its place an undamaged plate. It is also to be observedthat the fit between the interconnecting parts of the plate and thesupporting members is very loose whereby the plates may move limitedlyrelative to the supporting elements in order to expand freely andwithout binding.

As will be observed from Figure l, the rear edges of the plates overlapone another, and it is contemplated that this overlapping shall takeplace in the direction of thev discharge end of the hearth, for, ininstances where a continuous feeding yoperating across the hearth takesplace, a smooth and uninterrupted surface will be a'orded as contrastedwith a rough work engaging-surface which would loccur if the work werefedacross the hearth Kin the direction of the exposed rear edges of theheat resisting plates. In this latter event, the' work might catch onthe plates and displace them by swinging them' into a vertical position,or, if the castingsin the furnace are extremely heavy they might bendthe hot plates or otherwise damage the hearth. Owing to the fact thatrbyfar the greater amount ofmaterial in the heat resisting plates isdisposed in the rectangular bodies of the plates, as compared 'with thepockets ofthe plates, it will be appreciated that upon heat beingapplied, the greatest amount of expansion will be limparted to the iat,rectangular bodies, and notto the pockets and hence, with this in viewthe parts of the pocket are mounted for expansion within wide limits andeach body, portion is mounted 4for unlimited expansion independent-ly ofthe remaining plates, which it will be observed are free'to expandunlimit-edly without exerting any influence upon the adjacent sheets.

There are many additional features of this invention which are not atonce apparent to a person to whom the invention is disclosed, and "theseinclude, among other things, the provision of lug receiving/openingshaving symmetrical side walls disposed to permit the heat resistingplates to be inserted in the manner shown in Fgure 1, or reversed to runin the opposite direction; and the idea of mounting the connectingmembers on the under side of the work engaging heat resisting plateswhereby metal carried through the furnace may pass easily from eachoverlapping plate tc its underlying neighbor.

It will be appreciated from so much of the descripton as has alreadybeen given that one of the small heat resisting plates may be ofextremely high temperature while an adjacent plate may be relativelycool without the expansion of the hot plate being of damaging influenceupon that plate, or upon the adjacent cool plate. lt will further berealized that when all of the plates are heated the supporting rails ormembers may likewise become heated and tend to warp or buckle and, inorder to prevent this, it is contemplated attaching the supportingmembers to the furnace only at oneV end of each member so that it maycontract and expand freely towards and away from the opposite end of thefurnace. Either end of thel furnace may be employed as an anchorage forthe ends of the supporting members.

It is to be understood that in many aspects, the invention may bechanged and modified to depart from the illustrated embodiment thereof,and that parts may be eliminated or other parts provided, withoutdeparting from the true nature and scope of the invention as endeavoredto bepointed out by the foregoing description and the appended claims.For example, the overlapping character of the plates may even `bedispensed with and interengaging fingers provided along adjacent sideswhereby all of the plates will be disposed `within a single plane free'to contract and expandwhile at the same vtime presenting a satisfactorywork engaging surface; or, for example, the supporting elements may heeliminated from the combination in some instances and replaced byopenings formed directly in the furnace bottom or in other walls, etc.in connection with which the invention may be employed.

Having thus described my invention, what I claim as new and desire tosecure by United States Letters Patent is: j

r l. Asan improved article of manufacture,

a heat resisting plate comprising a flat up.

`engage a socket to hold said plate in place.

l. An assemblage of the character described comprising, in combination,a plurality of overlapping heat resisting members mounted for freesliding engagement with one another, and means associated with themembers for maintaining them in assembled relationship, said meanscomprising an elongated member provided at spaced intervals with platesecuring portions.

5. in assemblage of the character described comprising, in combination,a support having an opening formed therein, and a heat resist ing memberadapted to be carried by the support and. provided with a projection forinterittingly engaging within the opening.

6., An assemblage of the character described comprising, in combination,a support having a plurality of lug engaging portions formed thereon,and a plurality of heat resisting members mounted upon the support, eachof said heat resisting members being provided with a. lug forinterfitting engagement with i the lug engaging portions.

7. Ain assemblage of the character described comprising incombinatiom'an elongated supporting element, and a plurality of heatresisting plates hingedly connected to the supporting element, saidplates and said supporting element having interiitting parts soconstructed and arranged that any substantial displacement of the plateshorizontally relatively to the supporting element is prevented anddisplacement of the plate in. other directions relatively to thesupporting element is permitted only upon the plate being pivotallymoved into a vertically extending position.

8. An assemblage ofthe character described comprising, in combination, aplurality of elongated supporting members spaced apart and extendingparallel to one another, the supporting members being correspondinglyprovided with a plurality of, equally spaced, lug engaging openings, anda plurality of overlapping heat resisting plates carried bythesupporting members, each of the heat resisting plates being formedwith a plurality of downwardlyextending walls terminating in forwardlyextendin lugs adapted to engage within corresponding openings formed inthe supporting members substantially to prevent forward and rearwardmovement of the plate, and with a plurality of walls extendingrearwardlyfrom the downwardly exmeaeeo tending walls and adapted to engage thesides 0i" the supporting members substantially to prevent lateralmovements of lthe plate relatively to the supporting members.

9. A heat resisting furnace hearth compris ing a plurality of supportingmembers adapted to extend lengthwise of the hearth, the members beingprovided` with equally and correspondingly spaced openings, and aplurality of heat resisting plates overlapping in the direction of thedischarge end of the hearth, the plates being provided with projects forengaging Within the openings in the supporting members to preventaccidental displacement of the plates.

lO. As an improved article of manufacture, a solid monolithic plate ofheat resisting material having a lug oiliset therefrom near one endthereof and extending nearly parallel therewith in the general directionof an eX- tension oi: said end, said lug being adapted to engage asocket to hold said plate in place errcept when said plate has beenpivoted substantially 90 about said lug.

Signed at Chicago, illinois, this 19 day of September, 199.8.

FRANK A. FAHRENlWALD.

ITG

